2023 September;53(3)
Diving Hyperb Med. 2023 September 30;53(3):172−180. doi: 10.28920/dhm53.3.172-180. PMID: 37718290. PMCID: PMC10597601.
Delivering manual cardiopulmonary resuscitation (CPR) in a diving bell: an analysis of head-to-chest and knee-to-chest compression techniques
Graham Johnson1,2, Philip Bryson3, Nicholas Tilbury1, Benjamin McGregor4, Alistair Wesson4, Gareth D Hughes1, Gareth R Hughes1, Andrew Tabner1,2
1 University Hospitals of Derby and Burton NHS Foundation Trust, Royal Derby Hospital, Derby, UK
2 University of Nottingham Medical School, East Block, Lenton, Nottingham, UK
3 International SOS, Forest Grove House, Forrester Hill Road, Aberdeen, UK
4 No specified affiliation
Corresponding author: Dr Graham Johnson, University Hospitals of Derby and Burton NHS Foundation Trust, Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3NE, UK
ORCiD ID: 0000-0001-6004-6244
Keywords
Cardiovascular; Deaths; Diving deaths; Diving incidents; Diving medicine; Diving research; Resuscitation
Abstract
(Johnson G, Bryson P, Tilbury N, McGregor B, Wesson A, Hughes GD, Hughes GR, Tabner A. Delivering manual cardiopulmonary resuscitation (CPR) in a diving bell; an analysis of head-to-chest and knee-to-chest compression techniques. Diving and Hyperbaric Medicine. 2023 September 30;53(3):172−180. doi: 10.28920/dhm53.3.172-180. PMID: 37718290. PMCID: PMC10597601.)
Introduction: Chest compression often cannot be administered using conventional techniques in a diving bell. Multiple alternative techniques are taught, including head-to-chest and both prone and seated knee-to-chest compressions, but there are no supporting efficacy data. This study evaluated the efficacy, safety and sustainability of these techniques.
Methods: Chest compressions were delivered by a team of expert cardiopulmonary resuscitation (CPR) providers. The primary outcome was proportion of chest compressions delivered to target depth compared to conventional CPR. Techniques found to be safe and potentially effective by the study team were further trialled by 20 emergency department staff members.
Results: Expert providers delivered a median of 98% (interquartile range [IQR] 1.5%) of chest compressions to the target depth using conventional CPR. Only 32% (IQR 60.8%) of head-to-chest compressions were delivered to depth; evaluation of the technique was abandoned due to adverse effects. No study team member could register sustained compression outputs using prone knee-to-chest compressions. Seated knee-to-chest were delivered to depth 12% (IQR 49%) of the time; some compression providers delivered > 90% of compressions to depth.
Conclusions: Head-to-chest compressions have limited efficacy and cause harm to providers; they should not be taught or used. Prone knee-to-chest compressions are ineffective. Seated knee-to-chest compressions have poor overall efficacy but some providers deliver them well. Further research is required to establish whether this technique is feasible, effective and sustainable in a diving bell setting, and whether it can be taught and improved with practise.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Full article available here.
Diving Hyperb Med. 2023 September 30;53(3):181−188. doi: 10.28920/dhm53.3.181-188. PMID: 37718291. PMCID: PMC10597600.
An evaluation of the NUI Compact Chest Compression Device (NCCD), a mechanical CPR device suitable for use in the saturation diving environment
Andrew Tabner1,2, Philip Bryson3, Nicholas Tilbury1, Benjamin McGregor4, Alistair Wesson4, Gareth R Hughes1, Gareth D Hughes1, Graham Johnson1,2
1 University Hospitals of Derby and Burton NHS Foundation Trust, Royal Derby Hospital, Derby, UK
2 University of Nottingham Medical School, East Block, Lenton, Nottingham, UK
3 International SOS, Forest Grove House, Forrester Hill Road, Aberdeen, UK
4 No specified affiliation
Corresponding author: Dr Andrew Tabner, University Hospitals of Derby and Burton NHS Foundation Trust, Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3NE, UK
ORCiD ID: 0000-0003-4191-9024
Keywords
Cardiovascular; Deaths; Diving deaths; Diving incidents; Diving medicine; Diving research; Resuscitation
Abstract
(Tabner A, Bryson P, Tilbury N, McGregor B, Wesson A, Hughes GR, Hughes GD, Johnson G. An evaluation of the NUI Compact Chest Compression Device (NCCD), a mechanical CPR device suitable for use in the saturation diving environment. Diving and Hyperbaric Medicine. 2023 September 30;53(3):181−188. doi: 10.28920/dhm53.3.181-188. PMID: 37718291. PMCID: PMC10597600.)
Introduction: Provision of manual chest compressions in a diving bell using a conventional technique is often impossible, and alternative techniques are poorly evidenced in terms of efficacy and sustainability. The first mechanical cardiopulmonary resuscitation (CPR) device suitable for use in this environment, the NUI Compact Chest Compression Device (NCCD), has recently been designed and manufactured. This study assessed both the efficacy of the device in delivering chest compressions to both prone and seated manikins, and the ability of novice users to apply and operate it.
Methods: Compression efficacy was assessed using a Resusi Anne QCPR intelligent manikin, and the primary outcome was the proportion of compressions delivered to target depth (50–60 mm). The gold standard was that achieved by expert CPR providers delivering manual CPR; the LUCAS 3 mCPR device was a further comparator.
Results: The NCCD delivered 100% of compressions to target depth compared to 98% for the gold standard (interquartile range 1.5%) and 98% for the LUCAS 3 when applied to both supine and seated manikins. The NCCD sometimes became dislodged and had to be reapplied when used with a seated manikin.
Conclusions: The NCCD can deliver chest compressions at target rate and depth to both supine and seated manikins with efficacy equivalent to manual CPR and the LUCAS 3. It can become dislodged when applied to a seated manikin; its design has now been altered to prevent this. New users can be trained in use of the NCCD quickly, but practise is required to ensure effective use.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Full article available here.
Diving Hyperb Med. 2023 September 30;53(3):189−202. doi: 10.28920/dhm53.3.189-202. PMID: 37718292. PMCID: PMC10597602.
Decompression procedures for transfer under pressure (‘TUP’) diving
Jan Risberg1, Pieter-Jan van Ooij2, Olav Sande Eftedal3
1 NUI, Bergen, Norway
2 Diving Medical Center, Royal Netherlands Navy, Den Helder, the Netherlands
3 Equinor, Trondheim, Norway
Corresponding author: Dr Jan Risberg, NUI, Gravdalsveien 245, 5165 Laksevåg, Bergen, Norway
Keywords
Bell diving; Decompression sickness; Decompression tables; Diving tables; Occupational diving
Abstract
(Risberg J, van Ooij P-J, Eftedal O. Decompression procedures for transfer under pressure (‘TUP’) diving. Diving and Hyperbaric Medicine. 2023 September 30;53(3):189−202. doi: 10.28920/dhm53.3.189-202. PMID: 37718292. PMCID: PMC10597602.)
Background: There is an increasing interest in ‘transfer under pressure’ (TUP) decompression in commercial diving, bridging traditional surface-oriented diving and saturation diving. In TUP diving the diver is surfaced in a closed bell and transferred isobarically to a pressure chamber for final decompression to surface pressure.
Methods: Tables for air diving and air and oxygen decompression have been compared for total decompression time (TDT), oxygen breathing time as well as high and low gradient factors (GF high and low). These have been considered surrogate outcome measures of estimated decompression sickness probability (PDCS).
Results: Six decompression tables from DadCoDat (DCD, The Netherlands), Defence and Civil Institute of Environmental Medicine (DCIEM, Canada), Comex MT92 tables (France) and the United States Navy (USN) have been compared. In general, USN and DCD procedures advised longer TDT and oxygen breathing time and had a lower GF high compared to MT92 and DCIEM tables. GF low was significantly higher in USN procedures compared to DCD and one of the MT92 tables due to a shallower first stop in many USN profiles compared to the two others. Allowance and restrictions for repetitive diving varied extensively between the six procedures. While USN procedures have been risk-assessed by probabilistic models, no detailed documentation is available for any of the tables regarding validation in experimental and operational diving.
Conclusions: Absence of experimental testing of the candidate tables precludes firm conclusions regarding differences in PDCS. All candidate tables are recognised internationally as well as within their national jurisdictions, and final decisions on procedure preference may depend on factors other than estimated PDCS. USN and DCD procedures would be expected to have lower PDCS than MT92 and DCIEM procedures, but the magnitude of these differences is not known.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Full article available here.
Diving Hyperb Med. 2023 September 30;53(3):203−209. doi: 10.28920/dhm53.3.203-209. PMID: 37718293. PMCID: PMC10735713.
Hyperbaric oxygen treatment in children: experience in 329 patients
Figen Aydin1
1 Department of Hyperbaric Medicine, University of Health Sciences, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey
Corresponding author: Dr Figen Aydin, Saim Çıkrıkçı Cad. No:59, 35110 Karabağlar/İzmir, Turkey
Keywords
Barotrauma; Carbon monoxide; Hearing loss sudden; Safety; Side effects
Abstract
(Aydin F. Hyperbaric oxygen treatment in children: experience in 329 patients. Diving and Hyperbaric Medicine. 2023 September 30;53(3):203−209. doi: 10.28920/dhm53.3.203-209. PMID: 37718293. PMCID: PMC10735713.)
Introduction: Paediatric patients, like adults, may undergo hyperbaric oxygen treatment (HBOT) in both life-threatening situations and chronic diseases. There are particular challenges associated with managing paediatric patients for HBOT. This paper documents the indications, results, complications, and difficulties that occur during HBOT for a large cohort of paediatric patients and compares them with adult data in the literature. Methods used to reduce these difficulties and complications in children are also discussed.
Methods: This was a 15-year retrospective review of paediatric patients treated with HBOT at two hyperbaric centres. Between January 2006 and June 2021, patients under the age of 18 who received at least one session of HBOT were included.
Results: Three hundred and twenty-nine paediatric patients underwent a total of 3,164 HBOT exposures. Two-hundred and fifty-four patients (77.2%) completed treatment as planned and 218 (66.5%) achieved treatment goals without complications. Two patients treated for carbon monoxide poisoning exhibited neurological sequelae. Amputation was performed in one patient with limb ischaemia. Middle ear barotrauma events occurred in five treatments. No central nervous system oxygen toxicity was recorded during the treatments.
Conclusions: This patient series indicates that HBOT can be safely performed in pediatric patients with low complication rates by taking appropriate precautions. The cooperation of hyperbaric medicine physicians and other physicians related to paediatric healthcare is important in order for more patients to benefit from this treatment. When managing intubated patients an anaesthesiologist may need to participate in the treatment in order to perform necessary interventions.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):210−217. doi: 10.28920/dhm53.3.210-217. PMID: 37718294. PMCID: PMC10751292.
Snorkelling and breath-hold diving fatalities in Australian waters, 2014 to 2018
John Lippmann1,2,3
1 Australasian Diving Safety Foundation, Canterbury, Victoria, Australia
2 Department of Public Health and Preventive Medicine, Monash University, Victoria, Australia
3 Royal Life Saving Society Australia, Sydney, Australia
Corresponding author: Dr John Lippmann, Australasian Diving Safety Foundation, PO Box 478, Canterbury, VIC 3126, Australia
Keywords
Diving deaths; Cardiovascular; Fatalities; Freediving; Immersion; Snorkelling; Spearfishing
Abstract
(Lippmann J. Snorkelling and breath-hold diving fatalities in Australian waters, 2014 to 2018. Diving and Hyperbaric Medicine. 2023 September 30;53(3):210−217. doi: 10.28920/dhm53.3.210-217. PMID: 37718294. PMCID: PMC10751292.)
Introduction: This study investigated snorkelling and breath-hold diving deaths in Australia from 2014–2018 and compared these to those from 2001–2013 to identify ongoing problems and assess the effectiveness of countermeasures.
Methods: Media reports and the National Coronial Information System were searched to identify snorkelling/breath-hold diving deaths for 2014−2018, inclusive. Data were extracted from witness and police reports, medical histories, and autopsies. An Excel® database was created and a chain of events analysis conducted. Comparisons were made with the earlier report.
Results: Ninety-one fatalities (78 males, 13 females, median age 48 years [range 16−80]) were identified with one third likely doing some breath-hold diving. Fifty-two of 77 with known body mass index were overweight or obese. Approximately two thirds were inexperienced snorkellers and 64 were alone. Fifty-one were tourists. Planning shortcomings, such as solo diving and diving in adverse conditions, as well as pre-existing health conditions and inexperience predisposed to many incidents. Primary drowning was the likely disabling condition in 39% of cases with drowning recorded as the cause of death (COD) in two thirds. Cardiac events were the likely disabling conditions in 31% although recorded as the COD in 21% of cases.
Conclusions: Increasing age, obesity and associated cardiac disease have become increasingly prevalent in snorkelling deaths and there is a need for improved health surveillance and risk management. Closer supervision of inexperienced snorkellers is indicated. Apnoeic hypoxia from extended breath-holding and poor supervision remain a problem. The increased risk of harvesting seafood in areas frequented by large marine predators needs to be appreciated and managed appropriately.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):218−223. doi: 10.28920/dhm53.3.218-223. PMID: 37718295. PMCID: PMC10735697.
Self-reported vitality and health status are higher in Dutch submariners than in the general population
Antoinette Houtkooper1, Thijs T Wingelaar1,2 , Edwin L Endert1, Pieter-Jan AM van Ooij1,3
1 Royal Netherlands Navy Diving and Submarine Medical Center, Den Helder, the Netherlands
2 Amsterdam UMC, location AMC, Department of Anaesthesiology, Amsterdam, the Netherlands
3 Amsterdam UMC, location AMC, Department of Pulmonology, Amsterdam, the Netherlands
Corresponding author: Dr Thijs Wingelaar, Royal Netherlands Navy Diving Medical Center, Rijkszee en Marinehaven, PO Box 10.000, 1780 CA, Den Helder, the Netherlands
Keywords
Long-term health surveillance; Naval medicine; Occupational health; Quality of life; Submarine medicine
Abstract
(Houtkooper A, Wingelaar TT, Endert EL, van Ooij PJAM. Self-reported vitality and health status are higher in Dutch submariners than in the general population. Diving and Hyperbaric Medicine. 2023 September 30;53(3):218−223. doi: 10.28920/dhm53.3.218-223. PMID: 37718295. PMCID: PMC10735697.)
Introduction: Living aboard submarines has a potential negative effect on health. Although studies have evaluated specific health hazards and short-term outcomes, long-term health effects have not been investigated in this population.
Methods: Veteran submariners were contacted through the veterans’ society and administered a World Health Organisation validated questionnaire (SF-36) assessing their physical, emotional, and social functioning. Scores were compared with those of the general (reference) population and scores in veteran submariners were differentiated by rank, time at sea and time in service. Statistical analyses were performed using the Wilcoxon signed rank and Kruskal-Wallis tests.
Results: Of the 1,025 submariners approached in December 2019, 742 (72.4%) completed and returned the questionnaire before July 2020. All 742 were men, of median age 68 (interquartile range [IQR] 59–76) years (range 34–99 years). Of these subjects, 10.3% were current smokers, 64.4% were former smokers and 23.7% had never smoked. Submariners scored significantly better (P < 0.001) than the general population on all eight domains of the SF-36. Except for ‘pain’ and ‘change in health status over the last year’, scores for all domains decreased with age. Scores were not significantly affected by smoking status, rank, service, and time at sea.
Conclusions: Dutch veteran submariners have better self-reported vitality and health status than the general Dutch population. Rank, service, and time at sea did not significantly affect scores of Dutch submariners.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):224−229. doi: 10.28920/dhm53.3.224-229. PMID: 37718296. PMCID: PMC10735708.
Outcomes of hyperbaric oxygen treatment for central and branch retinal artery occlusion at a major Australian referral hospital
Jeremy Williamson1, Anil Sharma1, Alexander Murray-Douglass1, Matthew Peters1, Lawrence Lee1, Robert Webb2, Kenneth Thistlethwaite2, Thomas P Moloney1,3
1 Department of Ophthalmology, Royal Brisbane and Women’s Hospital, Brisbane, Australia
2 Department of Hyperbaric Medicine, Royal Brisbane and Women’s Hospital, Brisbane, Australia
3 School of Medicine, University of Queensland, Brisbane, Australia
Corresponding author: Dr Thomas P Moloney, Department of Ophthalmology, Royal Brisbane and Women’s Hospital, Brisbane, Australia
Keywords
Blindness; Circulation; Ophthalmology; Retinal artery occlusion; Vision
Abstract
(Williamson J, Sharma A, Murray-Douglass A, Peters M, Lee L, Webb R, Thistlethwaite K, Moloney TP. Outcomes of hyperbaric oxygen treatment for central and branch retinal artery occlusion at a major Australian referral hospital. Diving and Hyperbaric Medicine. 2023 September 30;53(3):224−229. doi: 10.28920/dhm53.3.224-229. PMID: 37718296. PMCID: PMC10735708.)
Introduction: This study analysed the treatment outcomes of patients that received hyperbaric oxygen treatment (HBOT) for retinal artery occlusion (RAO) at the Royal Brisbane and Women’s Hospital in Brisbane, Australia between 2015 and 2021.
Methods: Retrospective study from patient records including 22 eyes from 22 patients that received HBOT for either central RAO (17 patients) or branch RAO (five patients). Patients received the Royal Brisbane and Women’s Hospital RAO protocol for their HBOT. Analysis included best corrected visual acuity pre- and post-treatment, subjective improvements, side effects and patient risk factors were also recorded.
Results: Improvement in best corrected visual acuity was LogMAR -0.2 for central RAO on average with 8/17 (47%) experiencing objective improvement, 5/17 (29%) experienced no change and 4/22 (24%) experienced a reduction in best corrected visual acuity. Subjective improvement (colour perception or visual fields) was reported in an additional 4/17 patients, resulting in 12/17 (71%) reporting improvement either in visual acuity or subjectively. There was no improvement in the best corrected visual acuity of any of the five patients suffering from branch RAO. Cardiovascular risk factors present in the cohort included hypertension, hypercholesterolaemia, previous cardiovascular events, cardiac disease and smoking. Limited side effects were experienced by this patient cohort with no recorded irreversible side effects.
Conclusions: Hyperbaric oxygen treatment appears a safe, beneficial treatment for central RAO. No benefit was demonstrated in branch RAO although numbers were small. Increased awareness of HBOT for RAO resulting in streamlined referrals and transfers and greater uptake of this intervention may further improve patient outcomes.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):230−236. doi: 10.28920/dhm53.3.230-236. PMID: 37718297. PMCID: PMC10735644.
Contemporary practices of blood glucose management in diabetic patients: a survey of hyperbaric medicine units in Australia and New Zealand
Brenda R Laupland1, Kevin Laupland2,3, Kenneth Thistlethwaite1, Robert Webb1,4
1 Hyperbaric Medicine Unit, Royal Brisbane and Women’s Hospital, Brisbane, Australia
2 Queensland University of Technology (QUT), Brisbane, Australia
3 Department of Intensive Care Services, Royal Brisbane and Women’s Hospital, Brisbane, Australia
4 Clinical Informatics, Digital Metro North, Metro North Health, Brisbane, Australia
Corresponding author: Dr Brenda Laupland, Hyperbaric Medicine Unit, Royal Brisbane and Women’s Hospital, Butterfield Street, Herston, Queensland, 4029 Australia
ORCiD ID: 0009-0005-4883-1932
Keywords
Blood sugar level; Diabetes; Hyperbaric oxygen treatment; Protocol; Questionnaire
Abstract
(Laupland BR, Laupland K, Thistlethwaite K, Webb R. Contemporary practices of blood glucose management in diabetic patients: a survey of hyperbaric medicine units in Australia and New Zealand. Diving and Hyperbaric Medicine. 2023 September 30;53(3):230−236. doi: 10.28920/dhm53.3.230-236. PMID: 37718297. PMCID: PMC10735644.)
Introduction: Blood glucose levels may be influenced by hyperbaric oxygen treatment (HBOT). Patients with diabetes mellitus commonly receive HBOT but there is a lack of standardised blood glucose management guidelines. We documented relevant contemporary practices applied for patients with diabetes treated in hyperbaric medicine units.
Methods: A survey was administered in 2022 to the directors of all 13 accredited hyperbaric units in Australia and New Zealand to identify policies and practices related to management of patients with diabetes receiving HBOT.
Results: Twelve of the 13 units routinely managed patients with diabetes. Three-quarters (9/12) used < 4 mmol·l-1 as their definition of hypoglycaemia, whereas the other three used < 5, < 3.6, and < 3 mmol·l-1. Units reported 26% (range 13–66%) of their patients have a diagnosis of diabetes of which 93% are type 2. Ten (83%) units reported specific written protocols for managing blood glucose. Protocols were more likely to be followed by nursing (73%) than medical staff (45%). Ten (83%) units routinely tested blood glucose levels on all patients with diabetes. Preferred pre-treatment values for treatments in both multiplace and monoplace chambers ranged from ≥ 4 to ≥ 8 mmol·l-1. Seven (58%) units reported continuation of routine testing throughout a treatment course with five (42%) units having criteria-based rules for discontinuing testing for stable patients over multiple treatments. Two-thirds of units were satisfied with their current policy.
Conclusions: This survey highlights the burden of diabetes on patients treated with HBOT and identifies considerable variability in practices which may benefit from further study to optimise management of these patients.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):237−242. doi: 10.28920/dhm53.3.237-242. PMID: 37718298. PMCID: PMC10735703.
A retrospective review of the utility of Chest X-rays in diving and submarine medical examinations
Willem AJ Meintjes1, LaDonna R Davids1,2, Charles H van Wijk1,2
1 Division of Health Systems and Public Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
2 Institute for Maritime Medicine, Simon's Town, Cape Town, South Africa
Corresponding author: Dr Willem AJ Meintjes, Division of Health Systems and Public Health, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
ORCiD ID: 0000-0002-4909-5421
Keywords
Fitness to dive; Health surveillance; Medicals – diving; Occupational health; Occupational diving; Radiological imaging; Respiratory
Abstract
(Meintjes WAJ, Davids LR, van Wijk CH. A retrospective review of the utility of Chest X-rays in diving and submarine medical examinations. Diving and Hyperbaric Medicine. 2023 September 30;53(3):237−242. doi: 10.28920/dhm53.3.237-242. PMID: 37718298. PMCID: PMC10735703.)
Introduction: Performance of routine chest X-rays (CXRs) in asymptomatic individuals to assess hyperbaric exposure risk is controversial. The radiation risk may overshadow the low yield in many settings. However, the yield may be higher in certain settings, such as tuberculosis-endemic countries. We evaluated the utility of routine CXR in diving and submarine medical examinations in South Africa.
Methods: Records of 2,777 CXRs during 3,568 fitness examinations of 894 divers and submariners spanning 31 years were reviewed to determine the incidence of CXR abnormality. Associated factors were evaluated using odds ratios and a binomial logistic regression model, with a Kaplan-Meier plot to describe the duration of service until first abnormal CXR.
Results: An abnormal CXR was reported in 1.1% per person year of service, yielding a cumulative incidence of 6.5% (58/894) of the study participants. Only four individuals had a clinical indication for the CXR in their medical history. A range of potential pathologies were seen, of which 15.5% were declared disqualifying and the rest (84.5%) were treated, or further investigation showed that the person could be declared fit.
Conclusions: In South Africa, a routine CXR has a role to play in detecting abnormalities that are incompatible with pressure exposures. The highest number of abnormalities were found during the initial examinations and in individuals with long service records. Only four individuals had a clinical indication for their CXR during the 31-year span of our study. Similar studies should be performed to make recommendations in other countries and settings.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):243−250. doi: 10.28920/dhm53.3.243-250. PMID: 37718299. PMCID: PMC10735645.
A retrospective review of divers treated for inner ear decompression sickness at Fiona Stanley Hospital hyperbaric medicine unit 2014–2020
Jeremy S Mason1, Peter Buzzacott2, Ian C Gawthrope1,3, Neil D Banham1
1 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Murdoch, WA, Australia
2 Prehospital, Resuscitation and Emergency Care Research Unit, Curtin School of Nursing, Curtin University, WA, Australia
3 University of Notre Dame, Fremantle, WA, Australia
Corresponding author: Dr Jeremy Mason, Department of Hyperbaric Medicine, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, WA, 6150, Australia
Keywords
Diving medicine; Diving research; ENT; Hyperbaric oxygen; Persistent (patent) foramen ovale (PFO); Right-to-left shunt; Vertigo
Abstract
(Mason JS, Buzzacott P, Gawthrope IC, Banham ND. A retrospective review of divers treated for inner ear decompression sickness at Fiona Stanley Hospital hyperbaric medicine unit 2014–2020. Diving and Hyperbaric Medicine. 2023 September 30;53(3):243−250. doi: 10.28920/dhm53.3.243-250. PMID: 37718299. PMCID: PMC10735645. )
Introduction: Inner ear decompression sickness (IEDCS) is increasingly recognised in recreational diving, with the inner ear particularly vulnerable to decompression sickness in divers with a right-to-left shunt, such as is possible through a persistent (patent) foramen ovale (PFO). A review of patients treated for IEDCS at Fiona Stanley Hospital Hyperbaric Medicine Unit (FSH HMU) in Western Australia was performed to examine the epidemiology, risk factors for developing this condition, the treatment administered and the outcomes of this patient population.
Methods: A retrospective review of all divers treated for IEDCS from the opening of the FSH HMU on 17 November 2014 to 31 December 2020 was performed. Patients were included if presenting with vestibular or cochlear dysfunction within 24 hours of surfacing from a dive, and excluded if demonstrating features of inner ear barotrauma.
Results: There were a total of 23 IEDCS patients and 24 cases of IEDCS included for analysis, with 88% experiencing vestibular manifestations and 38% cochlear. Median dive time was 40 minutes and median maximum depth was 24.5 metres. The median time from surfacing to hyperbaric oxygen treatment (HBOT) was 22 hours. Vestibulocochlear symptoms fully resolved in 67% and complete symptom recovery was achieved in 58%. A PFO was found in 6 of 10 patients who subsequently underwent investigation with bubble contrast echocardiography upon follow-up.
Conclusions: IEDCS occurred predominantly after non-technical repetitive air dives and ongoing symptoms and signs were often observed after HBOT. Appropriate follow-up is required given the high prevalence of PFO in these patients.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):251−258. doi: 10.28920/dhm53.3.251-258. PMID: 37718300. PMCID: PMC10735712.
Selecting optimal air diving gradient factors for Belgian military divers: more conservative settings are not necessarily safer
Sven De Ridder1,2, Nathalie Pattyn1, Xavier Neyt1, Peter Germonpré2
1 VIPER Research Unit, Royal Military Academy, Brussels, Belgium
2 Centre for Hyperbaric Oxygen Therapy, Military Hospital, Brussels, Belgium
Corresponding author: Sven De Ridder, Centre for Hyperbaric Oxygen Therapy, Military Hospital, Brussels, Bruynstraat 1, 1120 Brussels, Belgium
Keywords
Computers-diving; Decompression; Decompression sickness; Decompression tables; Diving; Simulation; Models
Abstract
(De Ridder S, Pattyn N, Neyt X, Germonpré P. Selecting optimal air diving gradient factors for Belgian military divers: more conservative settings are not necessarily safer. Diving and Hyperbaric Medicine. 2023 September 30;53(3):251−258. doi: 10.28920/dhm53.3.251-258. PMID: 37718300. PMCID: PMC10735712.)
Introduction: In 2018, the Belgian Defence introduced a commercial off-the-shelf dive computer (Shearwater Perdix™) for use by its military divers. There were operational constraints when using its default gradient factors (GF). We aimed to provide guidelines for optimal GF selection.
Methods: The Defence and Civil Institute of Environmental Medicine (DCIEM) dive tables and the United States Navy (USN) air decompression tables are considered acceptably safe by the Belgian Navy Diving Unit. The decompression model used in the Shearwater Perdix (Bühlmann ZH-L16C algorithm with GF) was programmed in Python. Using a sequential search of the parameter space, the GF settings were optimised to produce decompression schedules as close as possible to those prescribed by the USN and DCIEM tables.
Results: All reference profiles are approached when GFLO is kept equal to 100 and only GFHI is reduced to a minimum of 75 to prolong shallower stop times. Using the Perdix default settings (GFLO = 30 and GFHI = 70) yields deeper initial stops, leading to increased supersaturation of the ‘slower’ tissues, which potentially leads to an increased DCS risk. However, Perdix software does not currently allow for the selection of our calculated optimal settings (by convention GFLO < GFHI). A sub-optimal solution would be a symmetrical GF setting between 75/75 and 95/95.
Conclusions: For non-repetitive air dives, the optimal GF setting is GFLO 100, with only the GFHI parameter lowered to increase safety. No evidence was found that using the default GF setting (30/70) would lead to a safer decompression for air dives as deep as 60 metres of seawater; rather the opposite. Belgian Navy divers have been advised against using the default GF settings of the Shearwater Perdix dive computer and instead adopt symmetrical GF settings which is currently the optimal achievable approach considering the software constraints.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 September 30;53(3):259−267. doi: 10.28920/dhm53.3.259-267. PMID: 37718301. PMCID: PMC10735636.
Diving with psychotropic medication: review of the literature and clinical considerations
Abraham L Querido1,2, Chiel F Ebbelaar3,4,5, Thijs T Wingelaar2,6
1 Praktijk Querido, Hilversum, the Netherlands
2 Dutch Society of Diving and Hyperbaric Medicine, Bilthoven, the Netherlands
3 PharmC, consultancy for clinical psychopharmacology, Utrecht, the Netherlands
4 Leiden University Medical Center, Department of Dermatology, Leiden, the Netherlands
5 University Medical Center Utrecht, Department of Pathology, Division of Laboratories, Pharmacy and Biomedical
Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
6 Royal Netherlands Navy, Diving Medical Center, Den Helder, the Netherlands
Corresponding author: Dr Thijs T Wingelaar, Rijkszee en Marinehaven, 1780 CA Den Helder, the Netherlands
Keywords
Fitness-to-dive; Medications; Mental health; Pharmacology; Psychiatry; Scuba
Abstract
(Querido AL, Ebbelaar CF, Wingelaar TT. Diving with psychotropic medication: review of the literature and clinical considerations. Diving and Hyperbaric Medicine. 2023 September 30;53(3):259−267. doi: 10.28920/dhm53.3.259-267. PMID: 37718301. PMCID: PMC10735636.)
This review discusses the safety concerns associated with diving while using psychotropic medication and the limited literature available on the topic. Despite the risks, some divers continue to dive while taking these medications, and their reasons for doing so are unclear. The exact mechanisms of action of these drugs in hyperbaric environments are poorly understood. While current standards and advice for fitness-to-dive assessments are based on limited evidence and expert opinion, developing evidence-based strategies could improve patient care and optimise diving safety. This review appraises relevant literature in diving medicine and provides clinical perspectives for diving physicians conducting fitness-to-dive assessments on patients using psychotropic medication.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Review article
Diving Hyperb Med. 2023 September 30;53(3):268−280. doi: 10.28920/dhm53.3.268-280. PMID: 37718302. PMCID: PMC10597603.
A systematic review of electroencephalography in acute cerebral hypoxia: clinical and diving implications
Nicole YE Wong1,2, Hanna van Waart1, Jamie W Sleigh1,3, Simon J Mitchell1,2,4, Xavier CE Vrijdag1
1 Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
2 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
3 Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
4 Slark Hyperbaric Unit, North Shore Hospital, Auckland, New Zealand
Corresponding author: Dr Xavier CE Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland 1142, New Zealand
ORCiD: 0000-0001-5907-6083
Keywords
Diving research; Diving safety memos; Physiology; Neurology; Brain
Abstract
(Wong NYE, van Waart H, Sleigh JW, Mitchell SJ, Vrijdag XCE. A systematic review of electroencephalography in acute cerebral hypoxia: clinical and diving implications. Diving and Hyperbaric Medicine. 2023 September 30;53(3):268−280. doi: 10.28920/dhm53.3.268-280. PMID: 37718302. PMCID: PMC10597603.)
Introduction: Hypoxia can cause central nervous system dysfunction and injury. Hypoxia is a particular risk during rebreather diving. Given its subtle symptom profile and its catastrophic consequences there is a need for reliable hypoxia monitoring. Electroencephalography (EEG) is being investigated as a real time monitor for multiple diving problems related to inspired gas, including hypoxia.
Methods: A systematic literature search identified articles investigating the relationship between EEG changes and acute cerebral hypoxia in healthy adults. Quality of clinical evidence was assessed using the Newcastle-Ottawa scale.
Results: Eighty-one studies were included for analysis. Only one study investigated divers. Twelve studies described quantitative EEG spectral power differences. Moderate hypoxia tended to result in increased alpha activity. With severe hypoxia, alpha activity decreased whilst delta and theta activities increased. However, since studies that utilised cognitive testing during the hypoxic exposure more frequently reported opposite results it appears cognitive processing might mask hypoxic EEG changes. Other analysis techniques (evoked potentials and electrical equivalents of dipole signals), demonstrated sustained regulation of autonomic responses despite worsening hypoxia. Other studies utilised quantitative EEG analysis techniques, (Bispectral index [BISTM], approximate entropy and Lempel-Ziv complexity). No change was reported in BISTM value, whilst an increase in approximate entropy and Lempel-Ziv complexity occurred with worsening hypoxia.
Conclusions: Electroencephalographic frequency patterns change in response to acute cerebral hypoxia. There is paucity of literature on the relationship between quantitative EEG analysis techniques and cerebral hypoxia. Because of the conflicting results in EEG power frequency analysis, future research needs to quantitatively define a hypoxia-EEG response curve, and how it is altered by concurrent cognitive task loading.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Review article
Diving Hyperb Med. 2023 September 30;53(3):281−284. doi: 10.28920/dhm53.3.281-284. PMID: 37718303. PMCID: PMC10735667.
Investigation into the effect of hyperbaric hyperoxia on serum cardiac Troponin T levels as a biomarker of cardiac injury
Jack Marjot1, John Mackenzie1, Nigel Jepson2, Ewan Reeves1, Michael Bennett1
1 Department of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney
2 Department of Cardiology, Prince of Wales Hospital, Sydney
Corresponding author: Dr Jack Marjot, Department of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney, Australia
ORCiD ID: 0009-0002-0212-1343
Keywords
Biomarkers; Cardiovascular; Health; Heart; Hyperbaric oxygen treatment
Abstract
(Marjot J, Mackenzie J, Jepson N, Reeves E, Bennett M. Investigation into the effect of hyperbaric hyperoxia on serum cardiac Troponin T levels as a biomarker of cardiac injury. Diving and Hyperbaric Medicine. 2023 September 30;53(3):281−284. doi: 10.28920/dhm53.3.281-284. PMID: 37718303. PMCID: PMC10735667.)
Introduction: There is clinical equipoise as to whether hyperoxia is injurious to the myocardium, both in the setting of acute ischaemic insults and on the stable myocardium. This study examined the effect of extreme hyperoxia – in the form of hyperbaric oxygen treatment – on the myocardium through measurement of high-sensitivity cardiac troponin.
Methods: Forty-eight individuals were enrolled to undergo a series of 30 exposures to hyperbaric oxygen for treatment of non-cardiac pathologies. High-sensitivity troponin T was measured before and after each session.
Results: There was no clinically significant difference in troponin measurements following acute or recurrent sequential exposures to extreme hyperoxia, despite the studied patient population having a high rate of previous ischaemic heart disease or cardiovascular risk factors.
Conclusions: This study demonstrates that profound hyperoxaemia does not induce any measurable cardiac injury at a biochemical level. Neither is there a reduction in cardiac troponin to suggest a cardioprotective effect of hyperbaric hyperoxia. This provides some reassurance as to the cardiac safety of the routine use of hyperbaric oxygen treatment in management of non-cardiac pathology.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Short communication
Diving Hyperb Med. 2023 September 30;53(3):285−289. doi: 10.28920/dhm53.3.285-289. PMID: 37718304. PMCID: PMC10735701.
Atypical distally distributed cutis marmorata decompression sickness associated with unconventional use of thermal protection in a diver with persistent foramen ovale
Petra Magri Gatt1, Emily Diacono2, Lyubisa Matity3, Kurt Magri4
1 Department of Medicine, Mater Dei Hospital, Msida, Malta
2 University of Malta, Msida, Malta
3 Hyperbaric and Tissue Viability Unit, Gozo General Hospital, Victoria, Gozo
4 Baromedicine Department, Hyperbaric Unit, Mater Dei Hospital, Msida, Malta
Corresponding author: Ms Emily Diacono, University of Malta, Msida, Malta
Keywords
Decompression illness; Pathophysiology; Right-to-left shunt; Wetsuit
Abstract
(Magri Gatt P, Diacono E, Matity L, Magri K. Atypical distally-distributed cutis marmorata decompression sickness associated with unconventional use of thermal protection in a diver with persistent foramen ovale. Diving and Hyperbaric Medicine. 2023 September 30;53(3):285−289. doi: 10.28920/dhm53.3.285-289. PMID: 37718304. PMCID: PMC10735701.)
Cutis marmorata is a mottled, marbling, livedoid rash caused by vascular inflammation and congestion in cutaneous decompression sickness. It may occur during or after ascent due to the formation of bubbles from dissolved nitrogen accumulated throughout the dive. It is strongly associated with the presence of right to left shunts, particularly persistent (patent) foramen ovale (PFO). We report a case of cutis marmorata decompression sickness of an unusual pattern associated with unconventional use of thermal protection (a ‘shorty’ wetsuit worn over full suit) by a diver with a PFO. The patient also had neurological manifestations of decompression sickness. The distal lower limb pattern of involvement favours the hypothesis that cutis marmorata in humans is likely to be due to bubbles in the skin itself and/or adjacent tissues rather than cerebrally mediated.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Case report
Diving Hyperb Med. 2023 September 30;53(3):290-291. doi: 10.2890/dhm53.3.290-291. PMID: 37718305. PMCID: PMC10735711.
Commentary on Plogmark, et al. Agreement between ultrasonic bubble grades using a handheld self-positioning Doppler product and 2D cardiac ultrasound
Asya Metelkina1, Axel Barbaud1
1 Azoth Systems, Ollioules, France
Corresponding author: Axel Barbaud, Azoth Systems, 93 Forum de la Mediterranée, 83190, Ollioules, France
Keywords
Decompression sickness; Doppler; Risk Factors; Risk Management; Scuba diving; Venous gas emboli
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Letter to the Editor
Diving Hyperb Med. 2023 September 30;53(3):291. doi: 10.2890/dhm53.3.291. PMID: 37718306. PMCID: PMC10735709.
Response to Metelkina and Barbaud
Oscar Plogmark1,2, Carl Hjelte1,2,3, Magnus Ekström1, Oskar Frånberg2,4
1 Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund, Sweden
2 Swedish Armed Forces Diving and Naval Medicine Center, Swedish Armed Forces, Karlskrona, Sweden
3 Sahlgrenska University Hospital, Anesthesia and Intensive Care, Gothenburg, Sweden
4 Blekinge Institute of Technology, Department of Mathematics and Natural Science, Karlskrona, Sweden
Corresponding author: Oscar Plogmark, Sten Bergmans väg 21, 121 46 Johanneshov, Sweden
Keywords
Decompression sickness; Doppler; Risk Factors; Risk Management; Scuba diving; Venous gas emboli
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Letter to the Editor
Diving Hyperb Med. 2023 September 30;53(3):292. doi: 10.2890/dhm53.3.292. PMID: 37718307. PMCID: PMC10735702.
Carbon monoxide poisoning: lest we forget
Bruce Mathew1, Gerard Laden1
1 Clinical Hyperbaric Facility, Hull and East Riding Hospital, Hull, UK
Corresponding author: Bruce Mathew, Clinical Hyperbaric Facility, Hull and East Riding Hospital, Hull, UK
ORCiD ID: 0009-0008-0820-8291
Keywords
Diving; Fatality; Gas supply; Scuba; Surface supply; Toxicity
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Publication Type: Letter to the Editor